Exhaust fan and method of operating the same

ABSTRACT

The present invention provides an exhaust fan including a ventilation grille having a plurality of louvers extending across an exterior face of the grille. Two of the louvers can define an opening and can be oriented such that the interior of the fan is obscured from view of a person through the opening, when the person is positioned in the room such that the person&#39;s eyes are outside an area of the room defined by a first reference plane oriented at an angle of less than 25 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line and a third reference plane oriented at an angle of less than 25 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal line.

RELATED APPLICATIONS

The present application claims the benefit of prior-filed, co-pending Provisional Patent Application No. 60/989,656, filed Nov. 21, 2007, the contents of which is incorporate herein by reference.

FIELD OF THE INVENTION

The present invention relates to an exhaust fan and, more particularly, to an exhaust fan having a grille for obscuring an interior of the exhaust fan from view while also allowing a given airflow.

SUMMARY

In some embodiments, the present invention provides an exhaust fan supported on a ceiling in a room of a structure. The exhaust fan can include a housing having an air inlet, an air outlet, and an interior positioned between the inlet and the outlet. The exhaust fan can also include a motor and a fan driven by the motor. The fan can be supported in the interior of the housing and be operable to move at least 1415 liters per minute of air from the room, through the interior of the housing to a location exterior to the room. The exhaust fan can also include a ventilation grille extending across the air inlet and having a plurality of louvers extending across an exterior face of the grille. Two of the plurality of louvers can have an opening therebetween and be oriented such that the interior of the housing is obscured from view of a person through the opening, when the person is positioned in the room such that eyes of the person are outside an area of the room defined by a first reference plane oriented at an angle of less than 30 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line and a third reference plane oriented at an angle of less than 30 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal line. The horizontal reference line can extend through the opening between the at least two louvers. The second reference plane can be perpendicular to a floor of the room and extending across the face of the grille in a direction substantially parallel to the two of the plurality of louvers.

In addition, the present invention provides an exhaust fan supported on a ceiling in a room of a structure. The exhaust fan can include a housing having an air inlet, an air outlet, and an interior positioned between the inlet and the outlet. The exhaust fan can also include a motor and a fan driven by the motor. The fan can be supported in the interior of the housing and can be operable to move air from the room, through the interior of the housing to a location exterior to the room. The exhaust fan can also include a ventilation grille extending across the air inlet and having a plurality of louvers extending across an exterior face of the grille. The plurality of louvers each include a nose at a distal end and a tail at a proximate end, such that the nose has a greater width than the tail and the nose extends toward an adjacent louver. Two of the plurality of louvers can have an opening therebetween and be oriented such that the interior of the housing is obscured from view of a person through the opening, when the person is positioned in the room such that eyes of the person are outside an area of the room defined by a first reference plane oriented at an angle of less than 25 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line, and a third reference plane oriented at an angle of less than 25 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal reference line. The horizontal reference line can extend through the opening between the at least two louvers. The second reference plane can be perpendicular to a floor of the room and extend across the face of the grille in a direction substantially parallel to the two of the plurality of louvers.

The present invention also provides a method of ventilating a room of a structure. The method can include the acts of providing a housing having an air inlet, an air outlet, and an interior positioned between the air inlet and air outlet, driving a fan with a motor to move at least 1415 liters per minute of air from the room, between the plurality of louvers, and through the interior of the housing to a location exterior to the room, and obscuring the housing interior from view of a person through an opening defined between two of the plurality of louvers with a ventilation grille having an exterior surface and a plurality of louvers oriented at an angle of about 65 degrees with respect to the exterior surface such that when the person is positioned in the room so that eyes of the person are outside an area of the room defined by a first reference plane oriented at an angle of less than 25 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line and a third reference plane oriented at an angle of less than 25 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal line the person is unable to see the interior of the housing, the horizontal reference line extending through the opening between the at least two louvers. The second reference plane can be perpendicular to a floor of the room and extending across the face of the grille in a direction substantially parallel to the two of the plurality of louvers.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded perspective view of an exhaust fan according to some embodiments of the present invention.

FIG. 2 is an exploded perspective view of the exhaust fan of FIG. 1.

FIG. 3 is a perspective view of a grill of the exhaust fan of FIG. 1.

FIG. 4 is a cross-sectional view of the grill taken along 4-4 of FIG. 3.

FIG. 5 is an enlarged cross-sectional view taken from circle 5 of FIG. 4.

FIG. 6 is a perspective view of the grille of the exhaust fan of FIG. 1 mounted in a room of a structure and showing an area of the room from which an interior of the exhaust fan is obscured from view.

FIG. 7 is another perspective view of the grille and showing the area of the room from which the interior of the exhaust fan is obscured from view.

FIG. 8 is a top view of the room and also showing the area of the room from which the interior of the exhaust fan is obscured from view.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” and “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

Also, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like “central,” “upper,” “lower,” “front,” “rear,” and the like) are only used to simplify description of the present invention, and do not alone indicate or imply that the device or element referred to must have a particular orientation. In addition, terms such as “first”, “second,” and “third” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance.

FIGS. 1 and 2 illustrate an exhaust fan 10 including a fan housing 14 defining an interior 16. The exhaust fan 10 also includes a motor 22 and a fan wheel 26 for moving air into, through, and out of the exhaust fan 10. In the illustrated embodiment of FIGS. 1 and 2, both the motor 22 and the fan wheel 26 are positioned in the interior 16 of the housing 14. In other embodiments, one or both of the motor 22 and the fan wheel 26 can be located outside the housing 14. In addition, while the fan 26 of the illustrated embodiment of FIGS. 1 and 2 is a fan wheel 26, in other embodiments, the fan 26 can have other shapes and constructions, including, but not limited to, axial-flow fans, a centrifugal fan, a scroll fan, a cross-flow fan, etc.

In some embodiments, the exhaust fan 10 is employed to ventilate, illuminate, and/or heat a room, area, or space. With reference to the exemplary embodiment of FIGS. 1 and 2, the fan wheel 26 can draw air from the room into the fan housing 14 and exhaust the air to an exterior location through a wall or ceiling of the room, or alternatively, through a ducting system, to other, more remote locations.

In the illustrated embodiment, the fan housing 14 has a generally rectangular box-like shape with inlets and outlets located on opposite sides. In other embodiments, the fan housing 14 can have other shapes and orientations, such as, for example, a round, triangular, rectangular, trapezoidal, or any other polygonal cross-sectional shape, oval, irregular, and the like and can include inlets and outlets having other relative orientations. The fan housing 14 can form a base or frame for the exhaust fan 10, thereby providing points and areas of attachment for other components of the exhaust fan 10.

Some embodiments of the exhaust fan 10 include a louvered ventilation grille 30 connected to the fan housing 14. The illustrated exemplary fan housing 14 has a generally box-like shape with an open end (see FIGS. 1 and 2). The illustrated grille 30 has a generally rectangular shape (see FIGS. 3-5), but can instead take any other shape matching or substantially matching the shape of the fan housing 14. In other embodiments, the grille 30 can have a shape different than that of the fan housing 14 it covers or at least partially covers.

The grille 30 can be positioned over an air inlet 31 of the fan housing 14 to at least partially conceal the fan housing 14. In some embodiments (e.g., the embodiment illustrated in FIGS. 1-2), the air inlet 31 of the fan housing 14 is shaped and dimensioned to be received within an open end of the grille 30. In some embodiments, the grille 30 is formed from a molded plastic material, such as by one-shot plastic injection molding. In other embodiments, the grille 30 is formed from other materials (e.g., metals, ceramics, etc.).

With reference to FIGS. 3-5, the grille 30 can include first and second sets of apertures or openings extending between substantially parallel louvers of respective first and second sets of louvers 34, 42 for receiving a flow of air. The first set of louvers 34 can guide air (which can include moisture, steam, smoke, exhaust, and the like) into the fan housing 14. The louvers of the first and second sets 34, 42 extend across a face 35 of the grille 30.

In the illustrated embodiment of FIGS. 3-5, the second set of louvers 34 is positioned on an opposite side of the grille 30 from the first set of louvers 42. In other embodiments, the second set of louvers 42 can be positioned in other locations on the grille 30. By way of example only, the second set of louvers 42 in the illustrated exemplary embodiment is located at an end of the grille 30 and fan housing 14 opposite the first set of louvers 34 with a generally planar un-louvered middle portion 50 defined between the first and second sets of louvers 34, 42.

In the illustrated embodiment, and shown specifically in FIG. 4, each of the louvers of the first set of louvers 34 is angled toward the un-louvered portion 50 of the grille 30. Each of the louvers of the second set of louvers 42 is also angled toward the un-louvered portion 50, such that the angles of the louvers of the first and second sets of louvers, 34 and 42 respectively, are substantially equal, but facing in opposite directions. As illustrated in FIG. 5, the angle between each of the louvers 34 and the grille 30 is labeled as angle A. In some embodiments, the angle A of the louvers 34, 42 is between about 45 and about 85 degrees from vertical, see FIG. 5. In other embodiments, the angle A of the louvers 34, 42 is between about 55 and about 75 degrees from vertical. In still other embodiments, the angle A of the louvers 34, 42 is between about 60 and about 68 degrees from vertical. As explained below, the angle A of the louvers 34 can help to substantially conceal interior portions of the exhaust fan 10 from view from the exterior of the exhaust fan 10.

Because the first and second sets of louvers 34, 42 can be mirror images of each other, only the first set of louvers 34 will be described in detail, but the description is also applicable to the second set of louvers 42. As shown in FIG. 5, the louvers of the first set of louvers 34 extend outwardly from the grille 30. Each of the louvers of the first set of louvers 34 have a first end 54 and second end 58. The first end 54 of each of the louvers of the first set of louvers 34 is located toward the interior 16 of the grille 30 and includes a tail 62, whereas the second end 58 is spaced apart from the first end 54 and includes a nose portion 66. The nose 66 of one of the louvers of the first set of louvers 34 extends across and partially covers the opening between each of the adjacent louvers of the first set of louvers 34, although an end-most opening can be free or substantially free of a nose 66. This can help to further conceal or substantially conceal the housing 14 and other components positioned inside the grille 30 from view from the outside of the grille 30.

As shown in FIG. 5, the nose 66 can be angled at angle B from the tail 62. In some embodiments, angle B is between about 95 degrees and about 135 degrees. In other embodiments, angle B is between about 105 and about 125 degrees. In still other embodiments, angle B is between about 112 and about 120 degrees.

In some embodiments, the exhaust fan 10 can be oriented such that the louvers of the first and second sets 34, 42 provide considerable masking of the exhaust fan interior 16 from significant portions of a room in a structure. More particularly, the grille 30 can be oriented on the ceiling of a room so that a person standing in a doorway of the room or moving along a traffic flow path through the room is prevented from seeing the fan interior 16. For example, the louvers of the first and second set of louvers 34, 42 can be parallel to a travel path, such that, as a person moves along the travel path, the exhaust fan interior 16 is substantially concealed. Because the exhaust fan 10 is often installed in a bathroom, there is usually a sink, toilet and often a shower, bathtub, or other furniture, which can inhibit a person from straying far from a travel path and thereby inhibit the person from seeing into the exhaust fan interior 16 from other angles. Further, it is uncommon for an individual to look straight up above, so even if an individual could see the exhaust fan interior 16 from directly below, this is unlikely to occur.

The louvers of the first set of louvers 34 each have a height H between the first end 54 and the second end 58. In some embodiments, the height H is between about 0.1 and about 0.5 inches (between about 0.254 cm and about 1.27 cm). In other embodiments, the height H is between about 0.2 and about 0.3 inches (between about 0.508 cm and about 0.762 cm). In yet other embodiments, the height H is between about 0.25 and about 0.27 inches (between about 0.635 cm and about 0.686 cm).

The tail 62 of the louvers 34 has a width W1 that is substantially constant along the tail 62. In some embodiments, the width W1 (which is measured perpendicular to a length of the louvers of the first set of louvers 34) is between about 0.5 and about 1.0 inches (between about 1.27 cm and about 2.54 cm). In other embodiments, the width W1 is between about 0.7 and about 0.8 inches (between about 1.778 cm and about 2.108 cm). In yet other embodiments, the width W1 is between about 0.73 and about 0.74 inches (between about 1.854 cm and about 1.88 cm). The nose portion 66 has a width W2 that is greater than the width W1. In some embodiments, the width W2 is between about 0.075 and about 0.2 inches (between about 0.19 cm and about 0.508 cm). In other embodiments, the width W2 is between about 0.1 and about 0.12 inches (between about 0.254 cm and about 0.305 cm). In yet other embodiments, the width W2 is between about 0.111 and about 0.117 inches (between about 0.282 cm and about 0.297 cm). In each of these embodiments, the width W2 of the nose 66 is greater than the width W1 of the tail 62.

Adjacent louvers of the first set of louvers 34 are positioned on the grille 30 so that the tails 62 are spaced apart by length L1. In some embodiments, length L1 is between about 0.1 and about 0.2 inches (between about 0.254 cm and about 0.508 cm). In other embodiments, the length L1 is between about 0.15 and about 0.16 inches (between about 0.381 cm and about 0.406 cm). In yet other embodiments, the length L1 is between about 0.157 and about 0.159 inches (between about 0.399 cm and about 0.404 cm). Because the tail 62 on a louver 34 can have a different width than the nose 66, the distance between noses 66 of adjacent louvers 34 is defined by length L2, which can be different from length L1. In some embodiments, length L2 is between about 0.1 and about 0.2 inches (between about 0.254 cm and about 0.508 cm). In other embodiments, the length L2 is between about 0.15 and about 0.17 inches (between about 0.381 cm and about 0.432 cm). In yet other embodiments, the length L2 is between about 0.159 and about 0.161 inches (between about 0.404 cm and about 0.409 cm).

In some embodiments, such as the embodiment illustrated specifically in FIG. 4, the louvers of the first and second sets of louvers 34, 42 are oriented along a curve. In other embodiments, the louvers of the first and second sets of louvers 34, 42 are curved, as illustrated in FIG. 5. This can provide an aesthetically pleasing appearance and can provide greater air flow through the grille 30. Due to the arcuate curvature, some of the louvers of the first or second sets of louvers 34, 42 may have different shapes, dimensions, or relative spacing, such as angle A, angle B, height H and lengths (L1 and L2) between the individual louvers of the first and second sets of louvers 34, 42 than other louvers 34, 42 on the same grille 30. For example, the louvers of the first and second sets of louvers 34, 42 that are positioned farthest away from the un-louvered portion 50 may have a greater height H and/or a smaller angle A than louvers 34, 42 that are positioned closer to the un-louvered portion 50.

The illustrated embodiment has been tested to assure that the noise level of the exhaust fan 10 during operation is acceptable. The operating noise level of the grille 30 falls within an acceptable range with the advantage that the exhaust fan interior 16 is better concealed by the arrangement of the louvers 34, 42. For example, the noise level the grille 30 has been measured in sones. In an embodiment that includes a variable DC motor, the exhaust fan 10 can operate at various speeds, which affects the volume of air flowing through the louvers 34, 42 and the noise of the motor.

The illustrated embodiment has also been tested to assure that the velocity of air flow from the room, through the grille 30 to a location exterior to the room during operation is acceptable. The air flow through the grille 30 during operation also falls within an acceptable range with the advantage that the exhaust fan interior 16 is better masked by the arrangement of the louvers 34, 42.

Table I, shown below, illustrates various models having differing cubic feet per minute (CFM) ratings with the respective liters per minute rating and sone rating.

TABLE I CFM Liters/Minute Rating Rating Sones Rated 50 1415 <0.3 80 2264 <0.3 110 3113 0.7 150 4245 1.5

FIGS. 6-8 illustrate the ventilating exhaust fan 10 installed in a room of a structure, such as a bathroom 70. The illustrated bathroom 70 includes a ceiling 74 and a floor 78 and a plurality of walls 82A, 82B, 82C, 82D. Wall 82A is positioned a length of L5 away from wall 82C. In some embodiments, L5 is about 10′ (about 3.05 m) to represent a length of a larger than average bathroom 70. Although four walls 82A-82D are illustrated, more or fewer walls can be included, including but not limited to, alcoves in one or more corners of the bathroom 70. The ceiling 74 and floor 78 can be spaced apart a distance H5. An average residential ceiling height is about 8′ (about 2.44 m), but could be as low as 6′ (1.83 m) and as high as 10′ (3.05 m) or higher.

The bathroom 70 has a travel path along arrows 86 that a person would be most likely to travel in the bathroom 70. The travel path 86 can relate to the position of a doorway 90 and any furniture in the room, as shown in FIG. 8. The fan 10 can be positioned to provide sufficient ventilation, such as in middle of the bathroom 10 as illustrated in FIGS. 6-8. The fan 10 can also be oriented to substantially obscure or conceal the fan interior 16 by orienting the louvers 34, 42 to extend substantially perpendicular to the travel path 86, as shown in FIG. 6. This orientation can substantially conceal the interior of the fan 10 and provide a more aesthetic appearance, without sacrificing the air flow rates or the ability of the fan 10 to vent air out of the bathroom 70.

The louvers 34, 42 help to conceal the fan interior 16. However, in some embodiments, some of the fan interior 16 can be viewed in some locations below the fan 10. In order to further illustrate the impact of the louver shape, a region in which the fan interior 16 is visible is herein described. The region of visibility is the region in which a person is able to view at least a portion of the fan interior 16. The region boundaries are determined by the location of a person's eyes at which at least some visibility is possible. Outside the visibility region, the fan interior 16 is concealed from view by the shape and position of the louvers. The visibility region changes over different distances below the fan (i.e. persons of differing heights and ceilings of differing heights). However, interior ceilings, such as residential ceilings are often spaced about 8′ (about 2.44 m) from the floor.

FIG. 6 includes two examples demonstrating the region of visibility below the fan 10. A first example demonstrates the visibility region for a female of average height having an eye level at a height of H3 above the floor 78. In some embodiments, H3 is between about 4′6″ and about 5′6″ (between about 1.37 m and about 1.68 m). In other embodiments, H3 is between about 4′9″ and about 5′3″ (between about 1.45 m and about 1.6 m). In still other embodiments, H3 is about 5′0″ (about 1.52 m) above the bathroom floor. A female with a height of H3 would be capable of seeing the fan interior 16 directly below the fan 10 across a length L3, to define a visibility region across the room width, as indicated by the single cross-hatching. In some embodiments, L3 is between about 10″ and about 50″ (between about 25.4 cm and about 127 cm). In other embodiments, L3 is between about 20″ and about 40″ (between about 50.8 cm and about 102 cm). In yet other embodiments, L3 is between about 25″ and about 30″ (between about 63.5 cm and about 76.2 cm). A plane P3 is positioned a height H3 from the floor 78 and extends the length L3 across the depth of the room. The edges of plane P3 represent the area at eyelevel H3 in which a female of height H3 can at least partially see into the fan interior 16. An angle θ3 extends downwardly between the center of fan 10 and an edge of the plane P3. The angle θ3 can be calculated from the following equation θ3=tan⁻¹(1/2*L3/(H5−H3)). From this equation and the ranges mentioned above, in some embodiments θ3 is between about 10 and about 30 degrees. In yet other embodiments, θ3 is between about 15 and about 25. In still other embodiments, θ3 is between about 19 and about 22 degrees. In one specific example, H3 is equal to 5′0″ (1.52 m), thereby making L3 equal to about 27″ (68.6 cm) and θ3 equal to about 21 degrees.

A second example demonstrates the visibility region for a male of average height having an eye level about a height of H4 above the floor 78. The second example demonstrates the visibility region for a male of average height having an eye level at a height of H4 above the floor 78. In some embodiments, H4 is between about 5′ (about 1.52 m) and about 6′ (about 1.83 m). In other embodiments, H4 is between about 5′3″ (about 1.6 m) and about 5′9″ (about 1.75 m). In still other embodiments, H4 is about 5′7″ (about 1.7 m) above the bathroom floor. A male with a height of H4 would be capable of seeing the fan interior 16 directly below the fan 10 across a length L4, to define a visibility region across the room width, as indicated by the double cross-hatching. In some embodiments, L4 is between about 5″ and about 45″ (between about 12.7 cm and about 114 cm). In other embodiments, L4 is between about 10″ and about 30″ (between about 25.4 cm and about 76.2 cm). In yet other embodiments, L4 is between about 15″ and about 20″ (between about 38.1 cm and about 50.8 cm). A plane P4 is positioned a height H4 from the floor 78 and extends the length L4 across the depth of the room. The edges of plane P4 represent the area at eyelevel H4 in which a male of height H4 can at least partially see into the fan interior 16. An angle θ4 extends downwardly between the center of fan 10 and an edge of the plane P4. The angle θ4 can be calculated from the following equation θ4=tan⁻¹(1/2*L4/(H5−H4)). From this equation and the ranges mentioned above, in some embodiments θ4 is between about 5 and about 35 degrees. In yet other embodiments, θ4 is between about 10 and about 25 degrees. In still other embodiments, θ4 is between about 16 and about 20 degrees. In one specific example, H4 is equal to 5′7″ (1.7 m), thereby making L4 equal to about 9.4″ (23.4 cm) and θ4 equal to about 18 degrees.

FIG. 7 illustrates the ventilating exhaust fan 10 mounted to the ceiling 74 of a bathroom 70. Two louvers 34 are shown on the grille 30 and a substantially horizontal line 92 is drawn between the two louvers 34. A first reference plane P5 extends through the horizontal line 92 and downward from the grille 30. A second reference plane P6 extends through the horizontal line 92 and downward from the grille 30 perpendicular to the grille 30. The first reference plane P5 and the second reference plane P6 intersect along the horizontal line, and the first reference plane P5 extends at an angle of θ5 from the second reference plane P6. A third reference plane P7 extends through the horizontal line 92 and downward from the grille 30. The third reference plane P7 intersects the first reference plane P5 and the second reference plane P6 at the horizontal line 92. The third reference plane P7 extends at an angle of θ6 from the second reference plane P6. The first reference plane P5, the second reference plane P7 and the floor 78 form a triangular prism that bounds the region below the grille 30 in FIG. 7 in which an interior of the grille 30 is at least partially visible.

In some embodiments, angle θ5 the same or similar to angle θ6. In other embodiments, angle θ5 is less than angle θ6. In still other embodiments, angle θ5 is greater than angle θ6. For example, in some embodiments, angle θ5 is between about 17 and about 27 degrees. In other embodiments, angle θ5 is between about 19 and about 25 degrees. In yet other embodiments, angle θ5 is between about 21 and about 23 degrees. For example, in some embodiments, angle θ6 is between about 17 and about 27 degrees. In other embodiments, angle θ6 is between about 19 and about 25 degrees. In still other embodiments, angle θ6 is between about 21 and about 23 degrees.

A plane P3 is positioned within the visibility region, such that two corners of the plane P3 are adjacent the first reference plane P5 and two corners of the plane P3 are adjacent the third reference plane P7. Plane P3 is representative of eye height of a first individual. A plane P4 is representative of eye height of a second individual. Plane P4 is positioned above plane P3 and also positioned such that two corners of plane P4 are adjacent the first reference plane P5 and that two corners of plane P4 are adjacent the third reference plane P7. In some embodiments, the planes P3 and P4 of FIG. 7 are positioned at similar heights as planes P3 and P4 of FIG. 6. In other embodiments, planes P3 and P4 of FIG. 7 are positioned at different heights than planes P3 and P4 of FIG. 6.

FIG. 8 illustrates the bathroom 70 including the ventilating exhaust fan 10 and typical bathroom furniture, such as a sink 94, a bathtub, 98, a toilet 102 and a linen closet 106. The walking path 86 through the doorway 90 and between the furniture is illustrated. Two visibility regions are defined by L6 and L7. In some embodiments L6 and L7 are the same as L3 and L4, but in other embodiments L6 and L7 are different from L3 and L4. Visibility region lines defined by L6 and L7 are extrapolated outside the bathroom 70 in phantom. The widths of the visibility regions (L6, L7) are not necessarily constant and linear, as illustrated in the tapering lines outside the bathroom 70. For example, as an individual is spaced a great distance, such as 10′ (3.05 m) horizontally from the fan 10, the visibility region is different than if that same person were spaced 1′ (14.5 cm) horizontally from the fan 10. However, the visibility region lines are substantially linear for a distance that is greater than the width or length of an average bathroom 70. Therefore, in most or all bathrooms, the visibility region for a given height will be substantially linear across the length or width of the bathroom.

The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention. 

1. An exhaust fan supported on a ceiling in a room of a structure, the exhaust fan comprising: a housing having an air inlet, an air outlet, and an interior positioned between the inlet and the outlet; a motor and a fan driven by the motor, the fan being supported in the interior of the housing and being operable to move at least 1415 liters per minute of air from the room, through the interior of the housing to a location exterior to the room; and a ventilation grille extending across the air inlet and having a plurality of louvers extending across an exterior face of the grille, two of the plurality of louvers having an opening therebetween and being oriented such that the interior of the housing is obscured from view of a person through the opening, when the person is positioned in the room such that eyes of the person are outside an area of the room defined by a first reference plane oriented at an angle of less than 25 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line and a third reference plane oriented at an angle of less than 25 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal reference line, the horizontal reference line extending through the opening between the at least two louvers, the second reference plane being perpendicular to a floor of the room and extending across the face of the grille in a direction substantially parallel to the two of the plurality of louvers.
 2. The exhaust fan of claim 1, wherein a nose of one of the two of the plurality of louvers extends at least partially across the opening.
 3. The exhaust fan of claim 2, wherein the nose is oriented at an angle of about 120 degrees with respect to a tail of the louver.
 4. The exhaust fan of claim 3, wherein the tail of the louver has a first width in a direction substantially perpendicular to the airflow through the opening and the nose of one of the plurality of louvers has a second width, and wherein the second width is greater than the first width.
 5. The exhaust fan of claim 1, wherein the plurality of louvers each include a nose at an exterior end and a tail at an interior end, such that the nose has a greater width than the tail.
 6. The exhaust fan of claim 1, wherein the angle is less than 25 degrees.
 7. The exhaust fan of claim 1, wherein the louvers are oriented at an angle of between about 60 and about 68 degrees from the second reference plane.
 8. The exhaust fan of claim 1, wherein a space between two adjacent louvers has a first length at an interior end and a second length at an exterior end, such that the first length is greater than the second length.
 9. An exhaust fan supported on a ceiling in a room of a structure, the exhaust fan comprising: a housing having an air inlet, an air outlet, and an interior positioned between the inlet and the outlet; a motor and a fan driven by the motor, the fan being supported in the interior of the housing and being operable to move air from the room, through the interior of the housing to a location exterior to the room; and a ventilation grille extending across the air inlet and having a plurality of louvers extending across an exterior face of the grille, the plurality of louvers each including a nose at an exterior end and a tail at an interior end, such that the nose has a greater width than the tail, the nose extending toward an adjacent louver, two of the plurality of louvers having an opening therebetween and being oriented such that the interior of the housing is obscured from view of a person through the opening, when the person is positioned in the room such that eyes of the person are outside an area of the room defined by a first reference plane oriented at an angle of less than 25 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line, and a third reference plane oriented at an angle of less than 25 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal reference line, the horizontal reference line extending through the opening between the at least two louvers, the second reference plane being perpendicular to a floor of the room and extending across the face of the grille in a direction substantially parallel to the two of the plurality of louvers.
 10. The exhaust fan of claim 9, wherein a nose of one of the two of the plurality of louvers extends at least partially across the opening.
 11. The exhaust fan of claim 10, wherein the nose is oriented at an angle of about 120 degrees with respect to a tail of the louver.
 12. The exhaust fan of claim 11, wherein the tail of the louver has a first width in a direction substantially perpendicular to the airflow through the opening and the nose of one of the plurality of louvers has a second width, and wherein the second width is greater than the first width.
 13. The exhaust fan of claim 9, wherein the fan moves at least 1415 liters per minute of air from the room, through the plurality of louvers, to a location exterior to the room.
 14. The exhaust fan of claim 9, wherein the angle is less than 25 degrees.
 15. The exhaust fan of claim 9, wherein the louvers are oriented at an angle of between about 60 and about 68 degrees from the second reference plane.
 16. A method of ventilating a room of a structure, the method comprising the acts of: providing a housing having an air inlet, an air outlet, and an interior positioned between the air inlet and air outlet; driving a fan with a motor to move at least 1415 liters per minute of air from the room, between the plurality of louvers, and through the interior of the housing to a location exterior to the room; and obscuring the housing interior from view of a person through an opening defined between two of the plurality of louvers with a ventilation grille having an exterior surface and a plurality of louvers oriented at an angle of about 65 degrees with respect to the exterior surface such that when the person is positioned in the room so that eyes of the person are outside an area of the room defined by a first reference plane oriented at an angle of less than 25 degrees with respect to a second reference plane and intersecting the second reference plane along a horizontal reference line and a third reference plane oriented at an angle of less than 25 degrees with respect to the second reference plane and intersecting the second reference plane along the horizontal line the person is unable to see the interior of the housing, the horizontal reference line extending through the opening between the at least two louvers, the second reference plane being perpendicular to a floor of the room and extending across the face of the grille in a direction substantially parallel to the two of the plurality of louvers.
 17. The exhaust fan of claim 16, wherein a space between two adjacent louvers has a first length at an exterior end and a second length at an interior end, such that the first length is greater than the second length.
 18. The method of claim 16, further comprising orienting the first reference plane at an angle of less than 25 degrees from the second reference plane, and orienting the third reference plane at an angle of less than 25 degrees from the second reference plane.
 19. The exhaust fan of claim 16, wherein the plurality of louvers each include a nose at an exterior end and a tail at an interior end, such that the nose has a greater width than the tail.
 20. The method of claim 16, wherein a nose of one of the two of the plurality of louvers extends at least partially across the opening, and wherein the nose is oriented at an angle of about 120 degrees with respect to a tail of the louver. 